Seismic Collapse Probability and Life Cycle Cost Assessment of Isolated Structures Subjected to Pounding With Smart Hybrid Isolation System Using a Modified Fuzzy Based Controller

The possibility of pounding on isolated structures with surrounding moat walls is one of the concerns in the design of isolation systems, especially in pulse-type near-field earthquakes. This paper puts forward the seismic probability assessment of structures equipped with passive and smart hybrid isolation systems by considering pounding possibilities. This investigation is performed on isolated structures equipped with a high damper rubber bearing (HDRB) considering stiff moat walls around the structure. In the Hybrid isolation system, magnetorheological dampers (MR) are considered an adaptive dissipation energy device along with isolators using an optimized novel interval Type-2 fuzzy logic controller with adaptive red-zone function (IT2FS+RZF) to reduce pounding possibilities. The fragility curves of the building for various cases are determined using IDA analysis, and possible damage costs are evaluated by using exceedance probability in each damage level. This study concludes that the collapse probability of the isolated structures with restrains at the code-based distance is over the acceptable limit of ASCE 7-22. The smart additional damping system with the proposed controller reduces the possible damage cost of the building by about 64% compared to the uncontrolled system and puts the collapse probability of the structure in the acceptable range.

Degradation-Dependent Stress Relaxing Semi-Interpenetrating Networks of Hydroxyethyl Cellulose in Gelatin-PEG Hydrogel with Good Mechanical Stability and Reversibility

The mechanical milieu of the extracellular matrix (ECM) plays a key role in modulating the cellular responses. The native ECM exhibits viscoelasticity with stress relaxation behavior. Here, we reported the preparation of degradation-mediated stress relaxing semi-interpenetrating (semi-IPN) polymeric networks of hydroxyethyl cellulose in the crosslinked gelatin-polyethylene glycol (PEG) architecture, leveraging a newly developed synthesis protocol which successively includes one-pot gelation under physiological conditions, freeze-drying and a post-curing process. Fourier transform infrared (FTIR) confirmed the formation of the semi-IPN blend mixture. A surface morphology analysis revealed an open pore porous structure with a compact skin on the surface. The hydrogel showed a high water-absorption ability (720.00 ± 32.0%) indicating the ability of retaining a hydrophilic nature even after covalent crosslinking with functionalized PEG. Detailed mechanical properties such as tensile, compressive, cyclic compression and stress relaxation tests were conducted at different intervals over 28 days of hydrolytic degradation. Overall, the collective mechanical properties of the hydrogel resembled the mechanics of cartilage tissue. The rate of stress relaxation gradually increased with an increasing swelling ratio. Hydrolytic degradation led to a marked increase in the percentage dissipation energy and stress relaxation response, indicating the degradation-dependent viscoelasticity of the hydrogel. Strikingly, the hydrogel maintained the structural stability even after degrading two-thirds of its initial mass after a month-long hydrolytic degradation. This study demonstrates that this semi-IPN G-PEG-HEC hydrogel possesses bright prospects as a potential scaffolding material in tissue engineering.

The Analysis of Beam-Column Joint Reinforced with Cross Bars according to SK SNI T-15-1991-03 on Cyclic Loads

The primary structural component supporting the other structural loads in a building is the beam-column joint. It is considered a critical area of a building which needs to be accurately designed to ensure energy is dissipated properly during the occurrence of an earthquake. Beam-column joint has the ability to offer a proper structure required to transform cyclic loads in the inelastic region but also has a direct impact on the components connected to it during the occurrence of any failure. This is one of the reasons the beam-column connection needs to be designed carefully. Therefore, this study focused on designing a beam-column joint with reinforcement according to SK SNI T-15-1991 in order to withstand cyclic loads. The test specimen used was observed to have a concrete compressive strength of 19.17 MPa while the dimension of the beam was 120 x 30 x 40 cm and the column was 30 x 30 x 200 cm, having 8Ø13.4 mm bars with 310.03 MPa yield strength (fy) as well as Ø9.8-100 mm stirrup reinforcement with (fy) 374.59 MPa. The test was initiated through the provision of 0.75 mm, 1.5 mm, 3 mm, 6 mm, 12 mm, 24 mm monotonic cyclic loads at the end of the beam up to the moment the specimen cracked. A maximum load of 68.35 kN for the compression and 49.92 kN for the tension was required to attain the cyclic load capacity. The maximum load was attained at 50.98 mm displacement. Furthermore, beam-column with 23.93 mm displacement caused a reduction in capacity. Meanwhile, the load at 24 mm produced the cycle's highest dissipation energy of 13.25 but this can be increased through the addition of stirrups to provide stiffness in the joint. The stiffness value was also observed to have increased after the structural repairs.

Indirect estimation of turbulent mixing in western route of Indonesian throughflow

The Indonesian Throughflow (ITF) via its western path conveys mainly North Pacific water origin with Smax thermocline water and Smin intermediate water from its entry portal in Sangihe-Talaud arcs to the main outflow straits in Lombok, Ombai and Timor passage. Along its route, the throughflow water characteristics transforms significantly due to strong diapycnal mixing forced by internal tidal waves interaction along complex topography such as passages, sill, straits, and shallow islands chains. This paper reports a brief estimate of turbulent mixing profiles in Sangihe chains, and Makassar Strait. The CTD dataset are obtained from the year of maritime continent (YMC) Cruise in August 2019 on board the R.V. Baruna Jaya I. The Thorpe method is used to analysis dissipation energy ( ε ) and vertical diffusivity (Kz ) from CTD dataset. It is shown that the highest ε epsilon 5.87 × 10−7 Wkg −1 and Kz 4.42 × 10−3 m2s 1 are found in the Sangihe area. In Labani Channel and Dewakang Sill the averaged vertical diffusivity is much weaker at the order of 10−4 m 2s1. Thus, Sangihe Chains station have the highest values compared to other stations at depth 950-1000 meters.

Consideration of contribution of hot-electron injection to the resistive switching of sputter-deposited silicon oxide film

<p>This paper considers the contribution of hot electrons to the resistive switching of sputter-deposited silicon oxide films based on experiments together with semi-2D Monte Carlo simulations. Using various device stack structures, this paper examines the impact of hot-electron injection on resistive switching, where conduction-band offset and fermi-level difference are utilized. Support is found for the predictions that hot-electron injection reduces the switching voltage and this should reduce the dissipation energy of switching. It is predicted that two-layer metal stacks can significantly reduce the number of oxygen vacancies in the sputter-deposited silicon oxide film after the reset process. It is also demonstrated that, in unipolar switching, the number of E’ or E” centers of the sputter-deposited silicon oxide film is relatively large.</p>

Comprehensive Assessment of Left Intraventricular Hemodynamics Using a Finite Element Method: An Application to Dilated Cardiomyopathy Patients

In this paper, we applied a method for quantifying several left intraventricular hemodynamic parameters from 4D Flow data and its application in a proof-of-concept study in dilated cardiomyopathy (DCM) patients. In total, 12 healthy volunteers and 13 DCM patients under treatment underwent short-axis cine b-SSFP and 4D Flow MRI. Following 3D segmentation of the left ventricular (LV) cavity and registration of both sequences, several hemodynamic parameters were calculated at peak systole, e-wave, and end-diastole using a finite element approach. Sensitivity, inter- and intra-observer reproducibility of hemodynamic parameters were evaluated by analyzing LV segmentation. A local analysis was performed by dividing the LV cavity into 16 regions. We found significant differences between volunteers and patients in velocity, vorticity, viscous dissipation, energy loss, and kinetic energy at peak systole and e-wave. Furthermore, although five patients showed a recovered ejection fraction after treatment, their hemodynamic parameters remained low. We obtained several hemodynamic parameters with high inter- and intra-observer reproducibility. The sensitivity study revealed that hemodynamic parameters showed a higher accuracy when the segmentation underestimates the LV volumes. Our approach was able to identify abnormal flow patterns in DCM patients compared to volunteers and can be applied to any other cardiovascular diseases.

Failure mechanics analysis of AISI 4340 steel using finite element modeling of the milling process

A slot cutting operation is studied in this paper using a rotating/translating flat end milling insert. Milling operation usually comprises up-milling and down-milling processes. These two types of processes have different behaviors with opposite trends of the forces thus making the operation complex in nature. A detailed Finite Element (FE) model is proposed in this paper for the failure analysis of milling operation by incorporating damage initiation criterion followed by damage evolution mechanism. The FE model was validated with experimental results and good correlations were found between the two. The failure criteria field variable (JCCRT) was traced on the workpiece to observe the amount and rate of cutting during the machining process. It was found that the model was able to predict different failure energies that are dissipated during the machining operation which are finally shown to be balanced. It was also shown that the variation of these energies with the tool rotation angle was following the actual physical phenomenon that occurred during the cutting operation. Among all the energies, plastic dissipation energy was found to be the major contributor to the total energy of the system. A progressive failure analysis was further carried out to observe the nature of failure and the variation of stress components and temperature occurring during the machining process. The model proposed in this study will be useful for designers and engineers to plan their troubleshooting in various applications involving on-spot machining.

Effects of the Rock Bridge Ligament on Fracture and Energy Evolution of Preflawed Granite Exposed to Dynamic Loads

This paper aims to reveal the mechanical properties, energy evolution characteristics, and dynamic rupture process of preflawed granite under impact loading with different rock bridge angles and strain rates. A series of dynamic impact experiments were conducted along with the separate Hopkinson press bar (SHPB) testing system to analyze and study the overall rock fracture process. Under the impact load, the peak stress of granite increases with the increase of rock bridge angle and strain rate, but the increase gradually decreases. The peak strain also increases gradually with the increase of rock bridge angle, but there is an upper limit value; the total input strain energy increases with the increase of strain rate and rock bridge angle. It is shown that the higher the strain rate, the higher the unit dissipation energy, and the greater the degree of rock fragmentation. For rock under impact loads, the crack first initiates from the wing end of the prefabricated flaw, the preflaw closes gradually, and finally the crack propagates at the locking section leading to the coalescence of rock bridge. With the increase of strain rate, the fragmentation degree of the specimen increases asymptotically, and the average fragmentation size of the specimen decreases with the increase of strain rate. It is suggested that the stability of large rocked slopes is controlled by the locked section, and understanding the fracture evolution of the rock bridge is the key to slope instability prediction.

Simulation of the Uniaxial Mechanical Properties and Crack Evolution of Coal Pillar-artificial Dam in Abandoned Mines

The key to the construction of underground reservoirs in abandoned mines is the construction of coal pillar-artificial dams, and the choice of bonding parameters between the coal pillars and artificial dams is the deciding factor that determines the engineering stability. Based on the analysis of the force state of coal pillar-artificial dams, the influence of the interface angle was analyzed. Seven sets of coal pillar-artificial dam specimens were prepared and a PFC3D numerical model was constructed to carry out the uniaxial compression test without lateral pressure. Based on the strength, deformation, and energy evolution characteristics of the coal pillar-artificial dam, the influence of the angle of the coal pillar-artificial dam interface on the performance of the specimen was analyzed. The PFC3D model was used to investigate crack evolution, particle displacement, and spatial distribution. The research results showed that the force state of the coal pillar-artificial dam can be divided into three types: split bearing, shared bearing, and coordinated bearing, corresponding to three different constitutive models. The composite simulation curve showed obvious post-peak viscosity. The compressive strength, peak strain, and average dissipated energy curves of the coal pillar-artificial dam showed a unimodal trend that first increased and then decreased. The total energy and elastic energy of the coal pillar-artificial dam showed an increasing trend during loading. The dissipation energy curve increased obviously in the early stage, then flattened, and finally, decayed. The simulated initiation stress and damage stress of the coal pillar-artificial dam specimens were intermediate to that of the coal pillars and the artificial dams, which first increased and then decreased with the increase in inclination, reaching the peak at 70°. The failures of the single and combined models were both dominated by monoclinic splitting. As the inclination increased, the position of the main cracks gradually shifted downwards and then upwards.